Learning salience amoung [sic] features through contingency in the CEL framework

Determining which features in an environment are salient given a task, salience assignment, is a central problem in Machine Learning. A related phenomenon, contingency (the conditions under which relative salience among environmental features is acquired), is central to learning and memory in animal psychology. This paper presents an analysis of a set of empirical data on contingency and an algorithm for the salience assignment problem. The algorithm presented is implemented in a working computer program which interacts with a simulated environment to produce contingent associative learning corresponding to relevant behavioral data. The model also makes specific empirical predictions that can be experimentally tested

Combining numeric and symbolic learning techniques

Incremental learning from examples in a noisy domain is a difficult problem in Machine Learning. In this paper we divide the task into two subproblems and present a combination of numeric and symbolic approaches that yields robust learning of boolean characterizations. Our method has been implemented in a computer program, and we plot its empirical learning performance in the presence of varying amounts of noise

Generalized CMAC adaptive ensembles for concept-drifting data streams

In this paper we propose to use an adaptive ensemble learning framework with different levels of diversity to handle streams of data in non-stationary scenarios in which concept drifts are present. Our adaptive system consists of two ensembles, each one with a different level of diversity (from high to low), and, therefore, with different and complementary capabilities, that are adaptively combined to obtain an overall system of improved performance. In our approach, the ensemble members are generalized CMACs, a linear-in-the-parameters network. The ensemble of CMACs provides a reasonable trade-off between expressive power, simplicity, and fast learning speed. At the end of the paper, we provide a performance analysis of the proposed learning framework on benchmark datasets with concept drifts of different levels of severity and speed.This work is partially funded by grant CASI-CAM-CM (S2013/ICE-2845), DGUI-Comunidad de Madrid, and grants DAMA (TIN2015-70308-REDT), MINECO, and Macro-ADOBE (TEC 2015-67719-P), MINECO-FEDER-EU

Der alveolare Gebissstatus bei Leberzirrhose und seine Änderung nach Lebertransplantation : Ein neuer Ansatz für intra-individuelle Vergleiche

Studien vor und nach Lebertransplantation zeigen, dass der alveolare Knochenverlust bei Leberzirrhose ausgeprägter ist als bei Normalpersonen und dass sich dieser Verlust nach der Lebertransplantation wieder zu verbessern scheint. In der Literatur gibt es jedoch keine intra-individuellen Vergleichsstudien vor und nach einer Lebertransplantation, so dass diese keine weit reichenden Schlüsse erlauben. Ziel der Studie war daher der intra-individuelle Vergleich des Gebissstatus, insbesondere des alveolaren Knochenverlustes vor und nach Lebertransplantation. Methode: Vor und nach der Lebertransplantation wurden dieselben Patienten mit denselben Untersuchungsmethoden untersucht. Dieses Vorgehen ist statistisch korrekt aber im Ergebnis unbefriedigend, denn Zahnverluste erzeugen einen Bias: Gehen schlechte Zähne verloren, fehlen die betreffenden Differenzen was eine Besserung des alveolaren Knochenverlustes vortäuscht. Daher wurde in dieser Arbeit in Anlehnung an den Parodontalen Screening-Index (PSI-Code), welcher die Taschentiefe als Maß für den Schweregrad des Parodontalzustandes mit Grad 0 bis 4 erfasst, ein Zahnhalslängen-Code (ZHL-Code) entwickelt. Dieser gibt den Schweregrad des alveolaren Knochenverlustes von 0 bis 5 an und codiert auch fehlende Zähne. Damit können Vergleiche lückenlos auf jeden einzelnen Zahn bezogen, und durch Mittelwertbildung das gesamte Gebiss pauschal im Sinne eines alveolaren Gebissstatus beurteilt werden. Der intra-individuelle Vergleich ist damit für jeden Zahn, für den pauschalen Gebissstatus und für Zahngruppierungen, wie Frontzähne oder Molaren geeignet. Ergebnisse: Der Knochenverlust vor Transplantation betrug 5,0 ± 2,0mm und danach 4,2 ± 2,0mm. Die Differenz der Mittelwerte von 0,3mm täuschte eine Verbesserung vor, die aber vom Median (0,00mm) nicht bestätigt wurde. Der ZHL-Code ergab sowohl für seine Mittelwert- als auch für seine Median-Differenzen eine Zunahme um 0,18 bzw. 0,13 Einheiten, was eine Verschlechterung bedeutet: Diese beträgt rückgerechnet aus dem ZHL-Code im Mittel 0,36mm. Fazit: Im Gegensatz zu vorhergehenden Studien fand sich in der aktuellen Untersuchung nach Lebertransplantation keine Verbesserung des alveolaren Knochenverlustes im intra-individuellen prä-/post-OP-Vergleich.The alveolar dentition status of patients with liver cirrhosis and its change due to liver transplantation - a new approach for intra-individual comparisons- Studies before and after liver transplantation show that alveolar bone loss is more pronounced in liver cirrhosis than in healthy people and that this loss seems to improve again after liver transplantation. In the literature, however, there are no intra-individual comparative studies before and after liver transplantation, hence these do not allow reliable conclusions. Thus, the aim of the study was the intra-individual comparison of the dentition status, with in particular consideration of alveolar bone loss before and after liver transplantation. Methods: Before and after liver transplantation, the same patients were examined using the same examination methods. This procedure is statistically correct, but the result is unsatisfactory, because tooth loss introduces a bias: If bad teeth are lost, the appropriately relevant differences are missing mimicking an improvement of the alveolar bone loss. Therefore, a tooth neck length code (ZHL code) was developed in this work based on the Periodontal Screening Index (PSI code), which assesses the pocket depth as a measure of the severity of the periodontal condition with degrees 0 to 4. The ZHL code indicates the severity of alveolar bone loss from 0 to 5 and also encodes for missing teeth. This means that comparisons can be made for each individual tooth without gaps and, by averaging, the entire set of teeth can be assessed in terms of an alveolar dentition status. The intra-individual comparison is therefore suitable for every tooth, for the general dentition status and for tooth groupings, such as front teeth or molars. Results: Bone loss before transplantation was 5.0 ± 2.0mm and thereafter 4.2 ± 2.0mm. The difference in the mean values of 0.3mm simulated an improvement, but this was not confirmed when applying the median (0.00mm). The ZHL code showed an increase of 0.18 and 0.13 units respectively, for both its mean and median differences, which represents a deterioration of 0.36mm in average, calculated by the ZHL code. Conclusion: In contrast to previous studies, no improvement in alveolar bone loss was found in the current study after liver transplantation in intra-individual pre/post-OP comparison

Contingency and latency in associative learning : computational, algorithmic and implementation analyses

Contingency (the learned relative salience of environmental features) and latency (the learned timing of response to stimuli) are central phenomena of learning and memory. This paper provides a computational analysis of, and algorithms for, a set of empirical data on contingency and latency in classical and instrumental conditioning. These analyses are presented within the framework of an information-processing architecture that describes a set of modules which operate in parallel and asynchronously to store, retrieve and modify experiential information. The architecture (called 'CEL', for 'Components of Experiential Learning') provides a way of making explicit the interactions among a number of otherwise separate algorithms for related phenomena. The modules comprising the architecture each emerge from the operation of an indexed network memory. The algorithms presented are also implemented in working computer programs that interact with a simulated environment to produce contingent associative learning and differential response latencies that correspond to the relevant behavioral data. The model makes a number of specific empirical predictions that can be experimentally tested

A Comparative Study of the Valence Electronic Excitations of N_2 by Inelastic X-ray and Electron Scattering

Bound state, valence electronic excitation spectra of N_2 are probed by nonresonant inelastic x-ray and electron scattering. Within the usual theoretical treatments, dynamical structure factors derived from the two probes should be identical. However, we find strong disagreements outside the dipole scattering limit, even at high probe energies. This suggests an unexpectedly important contribution from intra-molecular multiple scattering of the probe electron from core electrons or the nucleus. These effects should grow progressively stronger as the atomic number of the target species increases.Comment: Submitted to Physical Review Letters April 27, 2010. 12 pages including 2 figure pages

Reexamining the Lyman-Birge-Hopfield band of N2

Motivated by fundamental molecular physics and by atmospheric and planetary sciences, the valence excitations of N2 gas have seen several decades of intensive study, especially by electron-energy-loss spectroscopy (EELS). It was consequently surprising when a comparison of nonresonant inelastic x-ray scattering (NIXS) and nonresonant EELS found strong evidence for violations of the first Born approximation for EELS when leaving the dipole scattering limit. Here we reassess the relative strengths of the constituent resonances of the lowest-energy excitations of N2, encompassed by the so-called Lyman-Birge-Hopfield (LBH) band, expanding on the prior, qualitative interpretation of the NIXS results for N2 by both quantifying the generalized oscillator strength of the lowest-energy excitations and also presenting a time-dependent density functional theory (TDDFT) calculation of the q dependence of the entire low-energy electronic excitation spectrum. At high q, we find that the LBH band has an unexpectedly large contribution from the octupolar w 1Δu resonance exactly in the regime where theory and EELS experiment for the presumed-dominant a 1Πg resonance have previously had substantial disagreement, and also where the EELS results must now be expected to show violations of the Born approximation. After correcting for this contamination, the a 1Πg generalized oscillator strength from the NIXS results is in good agreement with prior theory. The NIXS spectra, over their entire q range, also find satisfactory agreement with the TDDFT calculations for both bound and continuum excitations.This work was supported by the US Department of Energy, the Natural Sciences and Engineering Research Council (NSERC) of Canada, the Australian Research Council, the Research Funds of the University of Helsinki, and the Academy of Finland (Contract No. 1127462, Centers of Excellence Program 2006-2011, and National Graduate School in Materials Physics). A.R. acknowledges support by MICINN (FIS2010-21282-C02-01),ACI-promociona (ACI2009-1036), Grupos Consolidados UPV/EHU del Gobierno Vasco (IT-319- 07), and the European Community through e-I3 ETSF project (Contract No. 211956).Peer Reviewe